1. Field of the Invention
This invention relates to drive control technology for a brushless motor.
2. Description of the Related Art
Brushless motors known in the art include that disclosed in JP2001-298982A, for example.
In this prior art brushless motor, control is carried out using on/off signals from digital magnetic sensors. Specifically, the timing for reversing the polarity of the voltage applied to the magnet coils is determined using the on/off signals from the digital magnetic sensors.
A conventional brushless motor is typically furnished with a number m of sensors corresponding to m phase coil groups, with the drive signal of each phase coil group generated by a dedicated sensor for each phase. However, it has been found that since errors and variations are present in the sensor output of the sensors, if the drive signal for each phase is generated by a dedicated sensor for the phase, the drive signals for each of the phases may develop improper phasing, resulting in lower efficiency of the motor.